Conservation and Development in Northern Thailand. Proceedings of a Programmatic Workshop on Agro-forestry and Highland-Lowland Interactive Systems, Held at Chiang Mai, Thailand, 13-17 November 1978 (UNU, 1980, 114 pages)

Editorial note

Preface

Introduction

Programme on the use and management of natural resources

Highland-lowland interactive systems in the humid tropics and subtropics: The need for a conceptual basis for an applied research programme

Northern Thailand: The problem

Research reports

Implications of socio-economic, demographic. and cultural changes for regional development in northern Thailand

Agricultural intensification and the role of forestry in northern Thailand

Problems of land use and recent settlement in Thailand's highland-lowland transition zone

Local climatological differences between highlands and lowlands in Thailand

Land use and its relationship to agriculture in Pangsa, Chiang Rai: A case study

Increasing farm production in the highlands of northern Thailand

Research and training requirements

Research and training in southeast Asia in relation to priority areas of the programme on the use and management of natural resources

On the significance of the watershed management approach in studying highland-lowland interactive systems

(introductory text...)

Review of current research on agriculture in the highlands of northern Thailand

Subcommittee reports, plenary discussion, and recommendations

Report by the subcommittee on documentation, training, and personnel

Report by the subcommittee on mapping and cover-type data requirements

Report by the subcommittee on climate, soil. and soil erosion data requirements

Report by the subcommittee on socio-cultural, demographic, and economic aspects

Plenary session

Recommendations

Huai Thung Choa highland project

The Huai Thung Choa highland project: Status and opportunities

Appendix

Workshop participants, observers, and staff

Other UNU publications

Mapping landscape dynamics in the highlands and lowlands of northern Thailand

Michel Bruneau

Abstract

This study is based on the experience of six years of mapping landscape
dynamics (five maps published and two others in the process of being published)
drawn to different scales, based on a chronological series of aerial photographs
and Landsat images of Northern Thailand. This approach is particularly effective
for the analysis of occupied landscape and their dynamics, demonstrating the
impact of man upon the natural environment.

After having defined the notion of landscape, we attempt to show its
cartographic translation at different scales (large, intermediate, and small)
and its application in the study of the highlands and lowlands in Northern
Thailand. Finally, we try to demonstrate the importance of such a mapmaking
process for regional planning and for study of the land development problems of
this region.

The Landscape and Its Dynamic in Northern Thailand

The term ''landscape'' is used here in a purely physiognomic sense. It is the
visible, observable space in its entirety As the visible form of contact between
the biosphere, lithosphere, and hydrosphere, landscape is characterized by
natural vegetation that is more or less degraded, and by human use and
occupation of the soil in a given geomorphological framework. The study of
landscape, or of units of landscape,' requires a synthetic approach. beginning
from the actual. considered as a whole. taking each of its elements not
separately but in their interrelationships and combinations.

The aerial photograph and, more recently, the satellite image have given to
this notion of landscape its extreme richness. They are the faithful reflection
of landscape according to the various horizontal directions with real relative
surfaces and at comparable scales. Geographic documents par excellence. they
reveal landscapes in their completeness: natural settings that are more or less
transformed by the human groups that occupy or have occupied them.

Each (mappable) landscape or landscape unit is a combination of features
belonging to three different types of phenomena the physical-chemical setting
(relief. climate, bodies of water), the biological setting (the living plant and
animal communities), and the human use and occupation of these settings
(production methods and socio-economic organization).'These different phenomena
evolve according to very dissimilar chronological rhythms. Geological and
geomorphological elements evolve over a very long period of time. Soil and plant
cover are transformed in the course of shorter periods. As for the action of
social groups, they play a role on an even shorter timespan and conform to a
logic that is radically different from that of the first two orders of
phenomena. Seen from the historic perspective of a period of twenty or thirty
years, a view that one has when in possession of the available photographic
documents of the space under consideration, it is the last order of phenomena
(anthropic action) which is here analysed. In our study the dynamic of mapped
landscapes concerns the periods 1953 1972 and 1976 1977. These periods are rich
in socioeconomic transformations (passage from a precapitalistic economic system
to a merchant economic system) which have brought about important changes in the
landscapes themselves

The first aerial photographic coverage of Thailand dates from 1953 1954
(approximate scale of 1:50,000) and corresponds to a period when the methods of
economic production were still largely traditional and when demographic growth
had not as yet made its impact felt. The landscapes of that period are thus
still strongly influenced by the old form of society and civilization. In 1968
1970 (second aerial photographic coverage of Thailand at a scale of about
1:60,000), and even more in 1972 (coverage of some regions at a scale of
1:20,000) and more recently (satellite data beginning in 1973), modernization,
penetration of the merchant economic system, and demographic explosion mark and
at times even disrupt the landscapes. The dynamic of landscapes thus partly
reflects the dynamic of socio-economic developments.

Landscape can be divided into different units according to the scale at which
it is observed: large scale (1:20,000), small scale (1:1,000,000), and
intermediate scale (1 :250,000). The limits of each is the reflection of
geographic separations proper to its particular scale. For each of them we have
a sectioning of space into landscape units of a certain type which do not
necessarily interlock with each other. The significance of each unit must be
determined and the type of representation that is to be given by each of the
scales must be ascertained in order to show how they can be combined so as to
produce a deeper understanding of a whole region

Large-Scale Cartography of the Dynamic of Landscapes

For rural landscapes analysed here, the large scale is generally considered
to be 1 :25,000, but it can go as far as 1 :50,000. The landscapes presented are
either homogeneous physiognomic units belonging to a vegetation type or to its
different forms of degradation, or homogeneous types of soil utilization (for
example. paddy-fields).

In the colour maps produced from this scale of photography, the shades used
conform to the principles of H. Gaussen for the natural vegetation, from indigo
for the thick evergreen forests of the mountains to orange for the clear forest
of the piedmont. and employs greens or yellow-greens for the mixed or semi-dense
forests. Blue represents the paddyfields.

Landscape transformations are indicated by stripes or white bands alternating
with colour bands. These are. for example. the rai extracted by clearing the
forest on the pioneer front (Map of Si Satchanalai) or the anthropic savannah
(former opium rai) in the Doi Inthanon area. Recently developed paddy fields
have horizontal or slanted bands.

In the Karen zone of the Doi Inthanon area it has been possible to
distinguish. in addition to the swiddens of the year shown in yellow, three
stages of recovery of the vegetation on fallow and (aerial photographs at a
scale of 1 :20,000 taken in 1972): a recent fallow strip (1 to 2 years) in a
state of low thickets, an old one (3 to 5 years) in the thicket state. and a
much older fallow strip (6 to 10 years) in a pre-forest state. Each is
represented with a range of colours extending from yellow-green to dark green.
the green darkens as the strip approaches the forest state. It is therefore
possible to perceive the cycle of the Karen fallow strips which cover a period
of 5 to 10 years, depending upon the site.

On the transect of Phrom Phiram the colours used on the two preceding maps
with an ecological meaning are replaced by hachures running in various
directions. The horizontals correspond to the wettest environments. flooded the
longest (swampy meadow). Rotation of the hachures in a counterclockwise
direction indicates drier and drier settings (swampy thicket, swampy forest,
semi dense forest). The more closely the 1968 physiognomy (aerial photographs
taken to a 1 :20,000 scale) approximates a forest state, the darker the zone is.
Increasingly pronounced human impact is depicted by progressively lighter tones.
Intermediate stages (a discontinuous thicket in the course of development) are
represented by bands that are alternately dark and light, the light band
indicating the transformation of the setting (in 1968) with relation to its
former state (in 1953)

Such principles enable one to procure a monochrome cartography of landscapes
and of their transformations on a relatively large scale (from 1 :20,000 to 1
:50,000). This representation of landscape units facilitates a rather detailed
analysis of ecological settings and of land use along particularly significant
transects.

The cartography of the dynamic of landscapes drawn to a large scale,
supplemented with maps of slopes. soils. and soil erosion. has a positive value
for the study of agroforestry systems in the highlands and lowlands. The map of
Doi Inthanon (1 :25,000), for example, enables one to analyse two of these
systems: the Karen system, where shifting cultivation with fallow strips on the
flanks and irrigated paddyfields in the valley bottoms increases towards
intensive use but without upsetting the basic ecological balance; and the Hmong
system. where the opium poppy and corn growing on the same parcels several yeses
in succession hinder the reconstitution of a forest plant cover, which instead
is replaced by a savannah.

The retreat of the dense or semi-dense forest of the mountains does not have
the same significance in each of these systems. A transition zone (intermediate
forest or wooded savannah) is found along the points of contact between these
two systems. The distribution of population and inhabited dwellings shows that
the Karen system can handle greater population densities than can the Hmong
system. However, recent growth of the latter (development of paddy-fields and
peach orchards) can orient it in the future towards an intensification of
agricultural techniques, as in the Karen case if the forest zones to be cleared
disappear and if the population stabilizes.

On the map of Sisatchanalai, two clearly contrasting zones can be seen. The
lowlands, consisting of valley bottoms and rolling low hills, where a pioneer
front of commercial crops is advancing very rapidly at the expense of the dense
and semidense forest, stand out from the highlands, where abandonment of
shifting cultivation or forest exploitation favours forest regeneration. Between
1953 and 1968 the farmed area had doubled. destroying the forest in over 13.5
per cent of the area mapped.

The transect of Phrom Phiram shows the progress of landdevelopment on the Mae
Nan flood plain between 1953 and 1968 and facilitates the derivation of the
dynamic from it without mapping the entire area.

Such large-scale mapping done with chronological series of aerial photographs
requires long and detailed work of interpretation, knowledge of design and of
the terrain involved. It can only be considered for areas particularly
representative of much larger entities. The main advantage of the transect
approach is that a maximum number of different environments car, be covered
while the mapped space is reduced to a minimum. These large-scale studies are
necessary in order to intensify the analysis of the landscape dynamics and to
understand their mechanisms by referring to surveys taken at the level of the
rural community or of a few communities. They can also be used for a perimeter
development which is at the same time a test zone (Huai Thung Choa. for example)

Intermediate - Scale Cartography

On the intermediate scale. Iandscape units are more complex. Each is defined
by a combination of traits, some belonging to the natural environment. others to
modifications and improvements brought about by human action. They have been
delimited either in relation to one or two dominant traits or in relation to the
combination of three or four traits. These landscapes-some simple and uniform in
structure, others complex and mosaic-have their own dynamic, which is governed
by human action. They often correspond to geomorphological units: valleys,
pediments, river banks, karst, and so on.

The map ''Soil Utilization and Landscapes in the North of Thailand"
gives a picture of the distribution of the large types of landscapes on
mountains. hills, and on the alluvial plains of the Chiang Mai and Lampang
basins in 1970. These landscapes evolved mainly in the mountains and on the
terraces, but this evolution during the course of a period of fifteen years is
translated better with a 1:20,000 or 1:50,000 scale map than with one of
1:250,000. The smaller scale does not lead to a very significant shifting of
limits. We thus contented ourselves with a cartography at a specific date (the
aerial photographs of 1968 to 1970). without directly translating the dynamic.

The natural or developed landscapes which have been little affected by recent
transformations appear in flat tones corresponding to the ecological mapping
principles of H. Gaussen (the wettest settings shown with the darkest colours.
the driest with light shades). Human action in the form of rai clearance is
shown with slanted bands: alternation of a colour band of the setting (type of
vegetation) and of a white band the width of which is proportional to the degree
of human action. The anthropic savannah of the highlands, which corresponds to
the opium poppy growing zone, is indicated with green broken lines of the same
colour as that of the mountain forest. which is the original formation. This map
shows the distribution of the major ecological systems and the degree of human
impact on the mountain environment the terraces, and pediments along the borders
of the basins or valleys.

The representation of the dynamic on this scale poses special problems
because of the great complexity of the landscape units. Sometimes the whole of
the landscape has been transformed, at other times one or two units among others
have changed during the 15-year period under consideration (map of the dynamic
of landscapes of the Sukhothai plain drawn to a scale of 1:250,000). The dynamic
is indicated with the absence or presence, the orientation, and spacing of
bands. Flat tones correspond to landscapes which either have not changed or have
changed very little. Width and spacing of the bands expresses the degree of
change. Slanted bands refer to the clearings in the highlands for the
cultivation of dry-weather crops, horizontal bands imply that there has been a
land development programme for the introduction of paddy-fields between the two
dates considered (1953 and 1968). We have been able to distinguish landscapes
that have been slightly, partially, or totally, transformed during the course of
the period studied. The number of bands joined for the same landscape unit is in
relation to the degree of complexity of this unit. Complex landscapes assure the
transition between two and at times three simple landscapes. These are the types
of transition that unite the traits of several simple contiguous units.

The map of Sukhothai, with slightly complex figures indicating a wide
diversity of situations, clearly shows the rapid progress of land development in
the course of these fifteen years. This includes the occupation of zones subject
to flooding and the older alluvions (uplands) between Mae Yom and Mae Nan and
the development of the pediments or hills along the borders of the plain,
especially for dry-weather crops or, less frequently. for paddy-fields

A comparison of the large-scale maps and those described above shows that the
legend has been simplified by about a third (for the same zone, there are, on an
intermediate scale map, three times fewer the number of units represented than
on a large scale map). This intermediate-scale cartography enables the
acquisition of a view of the whole province or small region, of the occupation
of the land and of its recent dynamic. Over a wide space, it simplifies and
generalizes the analytic data of a large-scale map while at the same time
retaining a sufficient precision as regards the localization and contours of the
landscape units.

Landsat Remote-Sensing Data and Small-Scale Cartography

On Landsat images, landscape units drawn to a small scale are more extended
and more uniform. In general. a trait of plant cover or of land use dominates
the unit and confers its homogeneity to it. There is often a connection between
these landscapes and large morphological-structural units.

Landsat images are of great value for studies conducted at a small scale.
Band 7 is useful for indicating the morphologicalstructural units. the wettest
zones and bush-burnt areas as well as the swidden. Band 5 provides an overall
view of plantcovered landscapes and of certain aspects of land use. Colour
composite images, combining bands 4, 5 and 7, are richer and more detailed with
better contrasts. For the mapping of landscapes in general, they are better than
band 5 (twelve landscape units instead of nine on the map of Northern Thailand).
but less clear than band 7 for swampy areas or wet surfaces.

A comparison between images taken at the beginning (December. January) and at
the end (March. April) of the dry season is possible and very instructive for
understanding Northern Thailand. Evergreen forests of the mountains and
anthropic savannahs can only be identified on the images of the beginning of the
dry season. while forest and clear thicket cannot be easily distinguished from
the semi-dense mixed forest except at the end of the dry season (the images of
March or April). Delimitation of the zone of irrigated farming and of the
stubble of dry paddy-fields is possible during both periods, but certain
phenomena of the use of the environment by man (swiddens or dry crops in an
advanced state of growth) appear only at one period (April) (Bruneau and Le Toan
1979). Rainy season images cannot be used because of the high cloud cover and
uniformity of the plant cover (green over the entire area). They can, on the
other hand, be useful for the study of floods and rice growing.

Very simple maps. plotted in black and white, were drawn after an
interpretation of three Landsat images that cover a large part of Northern
Thailand (Bruneau 1976). For this purpose. these images were enlarged to a scale
of 1:500,000. Enlargement to 1:250.000 is also possible for cartographic
purposes. But these Landsat images can only be interpreted correctly if based
upon a good knowledge of the terrain and in conjunction with aerial photograph
(1:20,000 to 1 :50,000) analysis of representative areas.

These images provide an overview of large areas far more effectively than
that obtained from a mosaic of aerial photographs. It is then possible to
delimit spatial units of the ''ecological regions" type which have a
certain homogeneity with regards to morphologic structure. phytogeography. Iand
utilization, and human occupation. Ecological variables that are preponderant on
this scale, generally of a geomorphologic nature, provide a unity to a group of
characters of a varied nature (vegetation. Iand use, soils, communication
routes, dwellings. ethnic groups) and enables the perception of the broad
integrity of the landscape (Bruneau 1976).

The repetition (theoretically every 18 days) of Landsat images and of their
sequences (since 1973 with Landsats 1, 2, and 3) has the great advantage over
aerial photographs of allowing a comparison between seasons and years, thus
facilitating the study of the dynamic of phenomena. The increase in the data
thus acquired will require more and more automatic processing and consequently a
systematic recourse to digital data. But this problem is still in a study stage.
The work of supervised classification and automated mapmaking can generally only
be performed on a small portion of the image.

An attempt was made to produce a supervised classification for a part of the
Doi Inthanon mountain region using four bands of the Landsat tape of 3 March
1975 (Bruneau and Le Toan 1979). The result is disappointing because of the
shadow cast, which falsified the classification of the forests. Only the paddy
fields in a stubble stage and the stretches of barren soil could be identified
without any ambiguity To overcome this problem, ancillary data must be
introduced through application of a more sophisticated software, as L.D Miller,
K Nualchawee, and C. Tom (1978) have done for a small mountainous area in the
vicinity of Chiang Dao. This technique is not yet operational for the
cartography of larger areas

Results, however, are far better in an irrigated plain region (the Chiang Mai
basin in the surroundings of San Patong). A supervised classification using
bands 5 and 7 on two different dates (27 July and 3 March 1975) provides a
precise cartography of the types of land use (6 in all) and of their changes
between the two dates. These studies will be continued in 1979 and 1980 with the
University of Chiang Mai, the objective being to produce an inventory of land
use and of its changes, with the aid of three tapes of Landsat digital data
(beginning and end of the dry season, five-year interval), for the whole of the
Chiang Mai basin

Although they represent future solutions, these techniques cannot, for the
moment. be applied efficiently except to restricted plains areas and thus are of
use only for studies made with large scale maps where they can complement the
analyses derived from aerial photographs.

Basic Documents for Rural Land Improvement and Development

The purpose of a cartography of the dynamic of landscapes is to locate and
measure the degree and intensity of human impact on the environment. In Northern
Thailand it brings into focus the transformations of the past 10 or 20 years
These landscape transformations are related to the increase in population
pressure and to penetration by the merchant economic system. which has caused an
expansion of dry commercial crops resulting in degradation of natural vegetation
types.

Whether it is in colour or monochrome, this cartography always has an
ecological basis which shows the main vegetation types and distinguishes rice
growing from dry crops, with the topography being expressed by contour lines. It
is really a basic map, more concise than a map of vegetation. For more
particular points, ecological conditions can be detailed in the insets:
hypsometry, bioclimates. geomorphology and slopes, and types of vegetation. The
main objective of the map-the human landscapes and their dynamic-is treated in
greater detail. The major land-use categories have been delimited and situated
chronologically in relation to each other; they often express the degree of
agriculture which is associated with them.

Between the natural landscapes (principal vegetation types) and the human
landscape (major land use), we have shown what can be called mixed landscapes in
which the human element is only partial. It is in this zone where the changes
that have occurred in the course of the past twenty years are most pronounced.
One sees in them either forms of degradation: natural plant formations evolving
towards their regrowth after abandonment, or more frequently, a progress of land
clearing accompanied by land development and dissappearance of the natural
vegetation.

Thanks to the topographical and ecological basis of these maps, a permanent
correlation can be established visually between the natural environment and the
use that man has made of it Thus an overview of the exploitation of ecological
settings by human groups is provided The dynamic perspective of this
representation of human landscapes is fundamental. The stages of the
implementation of changes and the direction taken in the growth phases,
including those that will appear in the near future. emerge from it.

The approach using different scales is necessary, especially for the small
and large scales. For the first. Landsat imagery can be used profitably only by
complementing it with a sampling of aerial photographs and with observations
made in the field. The Landsat images are of interest both before undertaking a
regional study and once it is completed. When a region is poorly known, they
enable one to acquire more rapidly than from aerial photographs an overview of
the terrain that is. however, still imprecise This approach also enables one to
locate the areas that present problems, especially if the region is rather vast
(more than 5,000 km²) One must then go to the large scale along a transect
chosen as particularly representative, or to small areas on which a development
action is exerted. The use of large scale aerial photographs and enquiries in
the field are then required. The Landsat images can then be re-examined for
generalization of the results thus obtained for a larger area.

Intermediate scales (between 1:60,000 and 1:250,000) are useful for the
improvement of small regions exceeding the framework of a small watershed or of
a small ecological or social unit (community or group of communities) which
belong to the large scale (between 1:5,000 and 1:30.000)

Aerial photographs at scales close to 1:50,000, generally available for
several periods (1954 and 1970), for they are employed to draw topographic maps,
are easily used for this purpose The districts (Amphoe) of Mae Taeng, Chiang
Dao, and Pail which form a group of highlands and lowlands in the vicinity of
the perimeter of Huai Thung Chao, can thus be mapped at 1:100,000. This would
enable the land improvement project under consideration to be situated in its
immediate regional setting. At a smaller scale (1 :500,000), the watershed of
the Mae Ping, to the North of Chiang Mai, and that of the Salween River basin in
the same latitudes and extending as far as the Burmese border. would furnish.
with the aid of Landsat images, a larger regional setting. This is considered
necessary in order to provide an overview of the phenomena in all their
complexity (savannahization of the highlands, main forestry ecosystems.
highland-lowland interactive systems).

Conclusion

In a project of integrated rural development, the cartography of inhabited
and man-created landscapes and of their dynamic is not a goal in itself but a
necessary intermediate stage. Made at different scales, it furnishes basic
documents that are at the same time analytic (large scales) and synthetic (small
scales), which constitute a kind of study support. These documents play a role
both at the beginning of such a research project, for clarifying objectives and
for posing problems, and towards the end, as spatial reference in order to
locate systems and structures, both ecological and socioeconomic. They
contribute to establishing a link between natural and human phenomena.